non-standard traceback types may cause failure in inspect.getframeinfo

[kingarrrt]

File ".venv/py27/lib/python2.7/site-packages/xtraceback/xtracebackexc.py", line 41, in XTracebackExc.__init__
    self = <xtraceback.xtracebackexc.XTracebackExc object at 0x426d750>
    etype = <type 'exceptions.KeyError'>
    value = KeyError('rows',)
    tb = <billiard.einfo.Traceback object at 0x425b290>
    xtb = <xtraceback.xtraceback.XTraceback object at 0x426d850>
      39 try:
      40     frame_info = inspect.getframeinfo(tb,
----> 41                                       self.xtb.options.context)
                                               i = 0
      42 except KeyError:  # pragma: no cover - defensive
      43     # <stdlib>/inspect.py line 506 - there may be no __main__
  File "<stdlib>/inspect.py", line 1000, in getframeinfo
    frame = <billiard.einfo.Traceback object at 0x425b290>
    context = 5
     998     frame = frame.tb_frame
     999 else:
--> 1000     lineno = frame.f_lineno
    1001 if not isframe(frame):
    1002     raise TypeError('{!r} is not a frame or traceback object'.format(frame))
AttributeError: 'Traceback' object has no attribute 'f_lineno'